Nic Salts vs Freebase vs Shortfills: Which E-Liquid Should You Use?

Nic salts, freebase e-liquids and shortfills are the three main types of e-liquid sold in the UK, and the difference comes down to the form of nicotine and how the bottle is supplied. Nic salts use a salt form of nicotine that feels smoother at higher strengths and suit low-power mouth-to-lung pods. Freebase is the traditional form, usually sold at lower strengths in 10ml bottles. Shortfills are larger bottles of nicotine-free e-liquid with space left to add a nicotine shot.

Picking the wrong type is one of the most common reasons a new kit feels harsh, weak or leaky. This guide explains how each type works, which devices it suits, how to mix a shortfill correctly, and how UK rules on bottle sizes, nicotine limits and the new duty affect each one. If you just want to browse, our e-liquids range covers all three.

The three e-liquid types at a glance

What are nic salts?

Nicotine salts are made by combining nicotine with an acid, commonly benzoic acid. This changes the chemistry so that higher strengths feel smoother on the throat than the same strength of freebase nicotine. That is why nic salts are usually sold at 10mg and 20mg, and why they are the standard liquid in most mouth-to-lung pod kits.

Nic salts are almost always 10ml bottles, and they are designed for low-power, higher-resistance coils. In a high-power sub-ohm setup, 20mg nic salt would produce a lot of vapour at a high strength, which most people find far too strong.

Popular nic salt ranges

Bar-style nic salts are designed to recreate the flavours of popular prefilled devices. At Wolfvapes you'll find ranges such as Elux Legend Nic Salts, Bar Juice 5000, Elf Bar Elfliq and Hayati Pro Max Nic Salts. Our bar-style nic salts compared guide sets the main ranges side by side, and the full nic salts collection lists every brand.

Who are nic salts best for?

• Adults using MTL pod kits with 0.8–1.2 ohm pods.
• People moving from prefilled pod kits, which almost always use 20mg nic salt.
• Anyone who wants a higher strength without a harsh throat feel.

What is freebase e-liquid?

Freebase is the original form of nicotine used in e-liquids. It has a sharper throat feel than nic salts, and that sharpness increases with strength. As a result, freebase is most often used at lower and middle strengths, commonly 3mg to 18mg in 10ml bottles.

Freebase 10ml liquids usually come in 50/50 or similar ratios, which wick well in most pods and small tanks. Some adults prefer the more noticeable throat hit of freebase, especially at lower strengths in RDL setups.

Who is freebase best for?

• Adults who want a lower strength in a pod kit or small tank.
• RDL vapers using 0.4–0.6 ohm pods, where high-strength nic salts can feel too strong.
• People who prefer a more noticeable throat hit.

What are shortfills?

A shortfill is a bottle of nicotine-free e-liquid that is deliberately under-filled. A 100ml shortfill usually comes in a 120ml bottle, and a 50ml shortfill in a 60ml bottle, leaving space for you to add nicotine shots if you want them.

Shortfills exist because UK rules limit nicotine-containing refill bottles to 10ml. A nicotine-free liquid isn't covered by that limit, so manufacturers can sell larger bottles and leave the choice of adding nicotine to the adult buyer. Browse shortfills or the 100ml e-liquids collection, with options such as Doozy Legends and Kingston AU Gold.

Most shortfills are high in VG, often 70/30, which produces dense vapour but is thicker. They are generally designed for higher-power kits and sub-ohm tanks rather than tight MTL pods, where thick liquid can struggle to soak into the coil.

How to mix a shortfill with nicotine shots

A nicotine shot is a 10ml bottle of unflavoured e-liquid containing nicotine, usually at 18mg/ml or 20mg/ml. Adding shots to a shortfill dilutes them across the whole bottle. Examples at Wolfvapes include the Nic Nic 18mg 50VG shot and the Nic Nic 20mg nic salt shot.

The calculation is simple: multiply the shot volume by its strength, then divide by the total volume. For example, 20ml at 18mg/ml contains 360mg of nicotine, and 360 divided by 120ml gives 3mg/ml.

Step by step

1. Remove the shortfill's nozzle tip, which usually pulls off.
2. Pour the nicotine shot or shots into the shortfill bottle.
3. Replace the tip and cap firmly.
4. Shake well for a minute or two so the nicotine is evenly mixed.
5. Label the bottle with its new strength and keep it out of reach of children and pets.

Check the bottle's stated capacity before adding shots, and don't overfill. Note that a nicotine shot also changes the VG/PG ratio slightly, depending on the shot's own ratio.

Which e-liquid works with which device?

Matching the liquid to the coil matters as much as matching flavour. Our MTL vs RDL coil resistance guide explains resistance and wattage in more detail, but the short version is:

Popular refillable pod kits such as the Vaporesso XROS 5 and OXVA Xlim Pro 2 are mainly designed for nic salts and 50/50 liquids. If your pod tastes burnt soon after filling with a thick shortfill, the liquid is likely too thick for the coil.

Is one type cheaper than the others?

Cost depends on the type and the size you buy. Bottled nic salts are typically cheaper per ml than prefilled pods, which our refillable vs prefilled pod kits cost guide covers in detail. Shortfills have historically worked out cheapest per ml, because they come in large bottles.

Since 1 October 2026, however, Vaping Products Duty applies at a flat £2.20 per 10ml to every type of vaping liquid, including nicotine-free shortfills and nicotine shots. A 100ml shortfill therefore carries £22 of duty, plus VAT. Retailers can sell older, pre-duty stock without duty stamps until 31 March 2027, so prices may change as that stock sells through. Our Vaping Products Duty explained article has the full timeline.

UK rules for each e-liquid type

The main rules, from the government's e-cigarette regulations guidance and the Tobacco and Vapes Act 2026, are:

• Nicotine-containing e-liquid (nic salts, freebase and nicotine shots) is limited to 10ml refill containers and a maximum strength of 20mg/ml.
• Nicotine-free shortfills are not covered by the 10ml limit, which is why they come in larger bottles.
• Age of sale: since 29 October 2026, it is illegal to sell any vaping product to under-18s, and that now includes nicotine-free e-liquids and shortfills. Buying them for someone under 18 is also an offence. See our Tobacco and Vapes Act explained guide.
• Duty: £2.20 per 10ml on all vaping liquids from 1 October 2026, with duty stamps required on all products from 1 April 2027.

Which e-liquid should you choose?

• Choose nic salts if you use an MTL pod kit, want 10mg or 20mg, or are switching from a prefilled pod kit.
• Choose freebase 10ml if you want a lower strength in a pod or small tank, or prefer a more noticeable throat hit.
• Choose shortfills if you use a higher-power kit or sub-ohm tank, vape at around 3mg or less, and are comfortable mixing in shots.
• Choose nicotine-free options if you don't want nicotine at all; unshotted shortfills and zero-nicotine vapes are available, but remember they are still 18+ only.

Frequently Asked Questions

What is the difference between nic salts and freebase?

Both contain nicotine, but in different chemical forms. Nic salts combine nicotine with an acid, which makes higher strengths feel smoother. Freebase is the traditional form and feels sharper as strength increases, so it is usually used at lower strengths.

Can I use nic salts in any vape?

Nic salts are designed for low-power, higher-resistance devices, typically MTL pod kits with 0.8 to 1.2 ohm pods. They are not suited to high-power sub-ohm tanks, where the strength would feel far too high.

Can I put shortfill in a pod kit?

Sometimes, but most shortfills are high-VG and thick, which can struggle to wick in small MTL pod coils and cause dry or burnt hits. Shortfills generally suit lower-resistance pods or sub-ohm tanks better. Check your pod's recommended liquid type.

How many nicotine shots do I add to a 100ml shortfill?

Adding two 10ml shots at 18mg/ml to a 100ml shortfill gives 120ml at 3mg/ml. Using 20mg/ml shots gives about 3.3mg/ml. Check the bottle has enough space before you add anything.

Why are nicotine e-liquids only sold in 10ml bottles?

UK regulations limit nicotine-containing refill containers to 10ml. Shortfills avoid this limit because they are sold without nicotine, leaving the adult buyer to add shots if they choose.

Are shortfills nicotine-free?

Yes, shortfills are sold containing no nicotine. They only contain nicotine if you add nicotine shots. Even so, since 29 October 2026 they can only be sold to adults aged 18 or over.

Do shortfills have vape duty on them?

Yes. Vaping Products Duty applies at £2.20 per 10ml to all vaping liquids from 1 October 2026, whether they contain nicotine or not. Older pre-duty stock can be sold until 31 March 2027.

What strength of nic salt should I use?

Nic salts are commonly sold at 10mg and 20mg. Many adults moving from prefilled pod kits start at 20mg, as that is the strength most prefilled pods use, while others prefer 10mg. The right strength is a personal choice.

Does nicotine strength affect flavour?

It can. Higher nicotine strengths, particularly in freebase, can add a peppery throat feel that some people notice alongside the flavour. Nic salts are designed to reduce that effect at higher strengths.

Final Verdict

There is no single best e-liquid type; each suits a different setup. Nic salts are the natural match for MTL pod kits and for anyone used to the 20mg strength found in prefilled pods. Freebase 10ml liquids work well at lower strengths and in looser RDL setups. Shortfills suit higher-power kits and tanks, give you a large bottle, and let you control the strength with nicotine shots.

Start with your device: check the pod's resistance and recommended liquid, then pick the type and strength that match. With Vaping Products Duty now applying to every type, including nicotine-free shortfills, it is worth comparing prices per ml as stock changes over the coming months.

This product contains nicotine, which is a highly addictive substance. For adults aged 18 and over only.